Table 1.
Clinical characteristics of the First Nations (FN) subjects with rheumatoid arthritis (RA) compared to FN controls and FN first‐degree relatives (FDRs) at the time of enrollment
| FN controls (n = 85) | FN FDRs (n = 109) | FN patients with RA (n = 95) | |
|---|---|---|---|
| Age at enrollment, mean ± SD years | 36 ± 12 | 38 ± 14 | 45 ± 14a |
| Sex, % female | 79 | 73 | 82 |
| Current smoker, % | 69 | 85b | 79 |
| RFc | |||
| Positive, no./total (%)d | 5/77 (6) | 11/105 (10) | 69/94 (73) |
| Titer, median (IQR) | 70 (216) | 103 (133) | 275 (581) |
| Anti‐CCPc | |||
| Positive, no./total (%)d | 4/85 (5) | 14/108 (13) | 67/93 (72) |
| Titer, median (IQR) | 82 (344) | 77 (40) | 200 (86) |
| RF or anti‐CCP positive, no./total (%)d | 14/78 (18) | 25/106 (24) | 76/93 (82) |
| RF and anti‐CCP positive, no./total (%)d | 2/77 (3) | 3/105 (3) | 61/93 (66) |
| SE positive, no./total (%)c | 41/69 (59) | 71/86 (83)e | 57/65(88)e |
P < 0.05 versus FN controls and versus FN FDRs; P < 0.0001 among all 3 groups, by Kruskal‐Wallis independent‐samples test.
P = 0.01 versus FN controls; P = 0.02 among all 3 groups, by chi‐square test.
Data on seropositivity for rheumatoid factor (RF), anti–cyclic citrullinated peptide (anti‐CCP) antibodies, and shared epitope (SE) were available from a subset of subjects. An RF titer of >50 AU was defined as positive. An anti‐CCP titer of >20 AU was defined as positive. Titers (expressed as median with interquartile range [IQR]) are reported only for antibody‐positive subjects.
P < 0.0001 among all 3 groups, by chi‐square test.
P = 0.001 versus FN controls.